Small Mammals of a Mine Waste Situation in the Central Adirondacks, New York: A Case of Opportunism by Peromyscus maniculatus

Abstract

Small mammals were liveand snap-trapped on poorly vegetated granitic mine wastes and in surrounding natural habitats in the central Adirondack Mountains, Essex Co., New York. The small mammal fauna on the mine wastes (seven species) was depauperate compared to that of the surrounding mixed hardwood forests (13 species). Only the woodland deer mouse, Peromyscus maniculatus gracilis (LeConte), was abundant on mine waste, comprising 83% of the small mammals captured. This constituted an atypical habitat for P. m. gracilis. The absence of other species was attributed to the lack of herbaceous cover or to inability to withstand the extremes of moisture or temperature. INTRODUCTION The pattern and extent of mammalian exploitation of a disturbed environment may be a measure of the ecological tolerance and niche plasticity of potential invaders from surrounding environments. The significance of a successful invasion by any species, will depend upon the degree to which the new environment differs from surrounding natural areas and the age of the novel environment. Research was conducted on small mammal colonization of an extensive, sparsely vegetated mine-waste habitat in the Adirondack Mountains of New York. Data were collected on the abundance, sex and age composition, distribution and movements of small mammals on the mine wastes. These data were compared with similar data collected on the small mammals inhabiting nearby natural areas. SITE The research was conducted at the MacIntyre Development of N.L. Industries, Inc., Tahawus, Essex Co. (Santanoni Quadrangle), N.Y. For the past 30 years, N.L. Industries, Inc. (formerly National Lead Company), has conducted open-pit mining operations at Tahawus for ilmenite (titanium) and magnetite (iron) ores. Overburden and waste rock from two mine pits have been deposited in a series of terraced disposal areas which now cover approximately 400 acres. These sites exhibit slow rates of ecological succession, contrasting markedly with the surrounding mixed deciduous forests. Trapping was conducted on waste areas ranging in age from 1-20 years, particularly those of 1215 years. Vegetation is a mosaic of clumps of young hardwoods, herbaceous vegetation and bare rock. Dominant trees are quaking aspen, Populus tremuloides, fire cherry, Prunus pensylvanicus, and white birch, Betula papyrifera. Trees are clumped on sites having sufficient soil to support